Airborne tree trimming apparatus

Abstract

An airborne tree trimming apparatus for installation on a helicopter or the like, and operating independently of the helicopter, which apparatus includes a boom extension vertically suspended from the helicopter and a plurality of circular saw blades arranged in tandem, coplanar relationship on an operating boom which is attached to the boom extension by means of a boom pivot. The circular saw blades are designed to rotate about parallel, substantially horizontal axes which are oriented substantially at right angles to the normal direction of motion of the helicopter and are belt-driven by an internal combustion engine which is also mounted on the operating boom, above the circular saw blades. A pair of ground-located cradles not attached to the operating boom, permit the apparatus to be landed with the operating boom elevated from ground level, by maneuvering the helicopter to lay the operating boom and circular saw blades on the cradles in front of the helicopter. An optional quick-release hook engaging the top of the boom structure and mounted on the helicopter permits the apparatus to be jettisoned in an emergency while the helicopter is airborne.

Having described my invention with the particularity set forth above, what is claimed is: 
     
       1. Airborne tree trimming apparatus for installation on a helicopter or the like, comprising boom means carried by said helicopter and extending downwardly from said helicopter; an internal combustion engine mounted on said boom means; blade means mounted on said boom means beneath said internal combustion engine; and power transmission means connecting said internal combustion engine and said blade means in driving relationship, whereby said blade means operates to cut and trim woody growth along a flight path beneath the helicopter or the like responsive to operation of said internal combustion engine. 
     
     
       2. Apparatus as recited in claim 1 wherein said blade means further comprises at least one circular saw blade rotatably mounted on said boom means. 
     
     
       3. Apparatus as recited in claim 2 wherein said at least one circular saw blade further comprises a plurality of circular saw blades rotatably mounted on said boom means in substantially coplanar, tandem relationship. 
     
     
       4. Apparatus as recited in claim 1 further comprising a boom pivot provided in said boom means between said helicopter and said internal combustion engine and wherein said boom means further comprises a boom extension projecting from said boom pivot to said helicopter and an operating boom extending from said boom pivot to said blade means. 
     
     
       5. Apparatus as recited in claim 4 wherein said blade means further comprises a plurality of circular saw blades rotatably mounted on said operating boom in substantially coplanar, tandem relationship. 
     
     
       6. Apparatus as recited in claim 4 wherein said boom extension extends downwardly substantially from the center of lift of the helicopter. 
     
     
       7. Apparatus as recited in claim 1 further comprising a quick-release hook carried by the helicopter for engaging said boom means, said quick-release hook remotely controlled from the helicopter for selectively separating said boom means from the helicopter and jettisoning said airborne tree trimming apparatus. 
     
     
       8. Apparatus as recited in claim 1 wherein said power transmission means further comprises drive pulley means provided in driving relationship on said internal combustion engine, at least one driven pulley means carried by said blade means and at least one drive belt engaging said drive pulley means and said driven pulley means. 
     
     
       9. Apparatus as recited in claim 3 wherein said power transmission means further comprises a drive pulley provided in driving relationship on said engine; a plurality of driven pulleys carried by said circular saw blades, respectively; a plurality of connecting belts connecting said driven pulleys to each other, respectively; and a drive belt engaging said drive pulley and one of said driven pulleys for driving said driven pulleys and said circular saw blades, respectively; and further comprising: (a) a boom pivot provided in said boom means between said helicopter and said internal combustion engine and wherein said boom means further comprises a boom extension projecting from said boom pivot to said helicopter and an operating boom extending from said boom pivot to said circular saw blades; and   (b) a quick-release hook carried by the helicopter for engaging said boom extension, said quick-release hook remotely controlled from the helicopter for selectively separating said boom extension from the helicopter and jettisoning said airborne tree trimming apparatus.   
     
     
       10. Apparatus as recited in claim 9 wherein said boom extension extends downwardly substantially from the center of lift of the helicopter. 
     
     
       11. Airborne tree trimming apparatus for installation on a helicopter or the like and cutting woody growth beneath the helicopter along the flight path of the helicopter, said apparatus comprising a boom extension having one end attached to said helicopter substantially at the center of lift of the helicopter, said boom extension being restrained from substantial rotation about the longitudinal axis thereof; a boom pivot provided on the opposite end of said boom extension; an operating boom extending from said boom pivot in substantially coplanar pivoting relationship with respect to said boom extension; a plurality of circular saw blades mounted in tandem on said operating boom for rotation substantially in a common plane, said circular saw blades oriented in close proximity to each other; an internal combustion engine fixedly carried by said operating boom between said boom pivot and said circular saw blades; and power transmission means connecting said internal combustion engine to said circular saw blades, for rotating said circular saw blades in concert and cutting the woody growth responsive to airborne operation of the helicopter and said internal combustion engine. 
     
     
       12. Apparatus as recited in claim 11 wherein said circular saw blades further comprise at least five circular saw blades. 
     
     
       13. Apparatus as recited in claim 11 wherein said boom pivot is adapted to facilitate articulation of said operating boom with respect to said boom extension substantially in a plane which extends through the longitudinal axis of the helicopter and the flight path. 
     
     
       14. Apparatus as recited in claim 12 wherein said circular saw blades are each about two feet in diameter. 
     
     
       15. Apparatus as recited in claim 11 further comprising a quick-release hook carried by the helicopter for engaging said boom extension, said quick-release hook remotely controlled from the helicopter for selectively separating said boom extension from the helicopter and jettisoning said airborne tree trimming apparatus. 
     
     
       16. Apparatus as recited in claim 11 wherein said power transmission means further comprises drive pulley means provided in driving relationship on said internal combustion engine; a plurality of driven pulley means carried by said circular saw blades, respectively; and a drive belt engaging said drive pulley means and one of said driven pulley means for driving said driven pulleys and said circular saw blades, respectively. 
     
     
       17. Apparatus as recited in claim 12 wherein: (a) said boom pivot is adapted to facilitate articulation of said operating boom with respect to said boom extension in a plane which extends substantially through the longitudinal axis of the helicopter; and   (b) said power transmission means includes a drive pulley provided in driving relationship on said internal combustion engine; a plurality of driven pulleys carried by said circular saw blades, respectively; a plurality of connecting belts connecting said driven pulleys, respectively; and at least one drive belt engaging said drive pulley and one of said driven pulleys, for driving said said driven pulleys and said circular saw blades, respectively; and further comprising a quick-release hook carried by the helicopter for engaging said boom extension, said quick-release hook remotely controlled from the helicopter for selectively separating said boom extension from the helicopter and jettisoning said airborne tree trimming apparatus.   
     
     
       18. Apparatus as recited in claim 17 further comprising an idler pulley rotatably carried by said boom extension, said idler pulley provided substantially in alignment with said drive pulley; a drive pulley belt connecting said idler pulley and said drive pulley in driving relationship; a drive belt pulley carried by said boom extension, said drive belt pulley adapted for rotation with said idler pulley; and wherein said drive belt is connected to said drive belt pulley and said driven pulleys, whereby rotation of said drive pulley causes rotation of said idler pulley and said drive belt pulley and said driven pulleys, for driving said circular saw blades, respectively. 
     
     
       19. The apparatus as recited in claim 18 wherein said circular saw blades are each about two feet in diameter and further comprising governor means connected to said internal combustion engine in speed-sensing and speed-controlling relationship. 
     
     
       20. Airborne helicopter-mounted tree trimming apparatus for cutting trees and woody growth at selected altitudes, said apparatus comprising boom mounting structure attached to the underside of the helicopter near the center of lift thereof; a boom extension having one end pivotally mounted to said boom mounting structure about a pivot axis which is horizontal and transverse to the principal direction of flight of said helicopter, said boom extension being restrained from substantial rotation about its longitudinal axis; an operating boom having one end hingedly carried by the opposite end of said boom extension, said operating boom pivotable with respect to said boom extension in a plane which extends substantially through the longitudinal axis of the helicopter; a plurality of circular saw blades mounted on said operating boom for rotation about companion axes which are substantially parallel to said pivot axis, respectively, said circular saw blades arranged substantially in a common plane in spaced, tandem relationship; an internal combustion engine mounted on said operating boom between said opposite end of said boom extension and said circular saw blades; and flexible power transmission means connecting said circular saw blades and said internal combustion engine in driving relationship, whereby said circular saw blades engage and cut the woody growth beneath the helicopter along a flight path at the selected altitudes responsive to operation of said internal combustion engine. 
     
     
       21. Apparatus as recited in claim 20 further comprising a quick-release hook carried by said boom mounting structure and engaging said boom extension, said quick-release hook remotely controlled from the helicopter for selectively separating said boom extension from said boom mounting structure and jettisoning said airborne tree trimming apparatus. 
     
     
       22. Apparatus as recited in claim 21 further comprising a frame carried by said operating boom and wherein said internal combustion engine is mounted on said frame. 
     
     
       23. Apparatus as recited in claim 21 wherein said flexible power transmission means further comprises a drive pulley carried by the power output of said internal combustion engine; a pair of driven pulleys carried by each of said circular saw blades, respectively; a drive belt connecting said drive pulley to a selected one of said driven pulleys; and a plurality of connecting belts connecting said driven pulleys to each other. 
     
     
       24. Apparatus as recited in claim 23 further comprising an idler pulley rotatably carried by said boom extension, said idler pulley provided substantially in alignment with said drive pulley; a drive pulley belt connecting said idler pulley and said drive pulley in driving relationship; a drive belt pulley carried by said boom extension, said drive belt pulley adapted for rotation in concert with said idler pulley; and wherein said drive belt is connected to said drive belt pulley and said driven pulleys, whereby rotation of said drive pulley causes rotation of said idler pulley and said drive belt pulley and said driven pulleys, for driving said circular saw blades, respectively. 
     
     
       25. Apparatus as recited in claim 24 further comprising a clutch mounted on said drive pulley for selectively engaging and disengaging said drive pulley and controlling the rotation of said circular saw blades. 
     
     
       26. Apparatus as recited in claim 25 further comprising a governor connected to said internal combustion engine for monitoring and controlling the speed of said internal combustion engine. 
     
     
       27. Airborne helicopter-mounted tree trimming apparatus for use with a helicopter having a selected cargo lift capacity, said apparatus comprising boom mounting structure attached to the underside of said helicopter near the center of lift thereof: a first boom pivotally mounted to said boom mounting structure about a pivot axis which is horizontal and transverse to the principal direction of flight of said helicopter, said first boom being restrained from substantial rotation about its longitudinal axis: a second boom hingedly connected to the lower end of said first boom; a plurality of circular saw blades rotatably mounted in tandem relationship on said second boom for rotation about axes which are parallel to said pivot axis, said circular saw blades oriented substantially in a common plane; an internal combustion engine carried by said second boom; and power transmission means connecting said internal combustion engine to said circular saw blades for rotating said circular saw blades at a selected speed responsive to operation of said internal combustion engine. 
     
     
       28. Apparatus as recited in claim 27 further comprising a quick-release hook carried by said boom mounting structure and remotely controlled from the helicopter for selectively separating said first boom from the helicopter and jettisoning said airborne tree trimming apparatus. 
     
     
       29. Apparatus as recited in claim 28 wherein said flexible power transmission means further comprises a drive pulley carried by the power output of said internal combustion engine; a pair of driven pulleys carried by each of said circular saw blades in spaced, substantially aligned relationship, respectively; a cog tooth drive belt connecting said drive pulley to a selected one of said driven pulleys; and at least one V-belt connecting said driven pulleys to each other, respectively, for driving said driven pulleys and said circular saw blades responsive to operation of said internal combustion engine. 
     
     
       30. Apparatus as recited in claim 29 further comprising an idler pulley rotatably carried by said boom extension, said idler pulley provided substantially in alignment with said drive pulley; a drive pulley belt connecting said idler pulley and said drive pulley in driving relationship; a drive belt pulley carried by said boom extension, said drive belt pulley adapted for rotation in concert with said idler pulley; and wherein said drive belt is connected to said drive belt pulley and said driven pulleys, whereby rotation of said drive pulley causes rotation of said idler pulley and said drive belt pulley and said driven pulleys, for driving said circular saw blades, respectively. 
     
     
       31. Apparatus as recited in claim 30 further comprising a clutch mounted on said drive pulley for selectively engaging and disengaging said drive pulley and controlling the rotation of said circular saw blades. 
     
     
       32. Apparatus as recited in claim 31 further comprising a governor connected to said internal combustion engine for monitoring and controlling the speed of said internal combustion engine. 
     
     
       33. Apparatus as recited in claim 30 further comprising a pair of cradle supports provided on the ground in spaced relationship for receiving and supporting said tree-trimming apparatus.